The present invention relates to a blood collecting needle. More specifically, this invention relates to a blood collecting needle in which one end of the needle is stuck in a blood vessel of a subject and another end of the needle is communicated with the inside of a vacuum blood collecting tube to allow the collection of blood in an amount corresponding to a negative pressure inside the vacuum blood collecting tube.
In performing clinical examination, for example, serum examination or blood cell examination, a blood collecting needle 51 as shown in FIG. 1, which comprises a hub 52, a needle tube 53 and a resilient cap 54, is ordinarily used. When the blood collecting needle 51 is rotated in the direction of the arrow shown in FIG. 1, a thread portion 521 of the hub 52 is engaged with a thread portion 551 on a distal end of a holder 55 and the blood collecting needle 51 is set at the distal end of the holder 55. In this state, a blade 531 on the distal end of the needle tube 53 is stuck in a blood vessel of a patient. Then, when a vacuum blood collecting tube (not shown) is inserted from an opening at the proximal end of the holder 55 into the inside of the holder 55, an edge 532 on the proximal end of the needle tube 53 is broken through the proximal end of the resilient cap 54 and then through a rubber stopper of the vacuum blood collecting tube which allows the inside of the blood vessel to communicate with the inside of the vacuum blood collecting tube. In this state, blood in an amount corresponding to a negative pressure inside the blood collecting tube is collected in the blood collecting tube.
However, the conventional blood collecting needle 51 shown in FIG. 1 requires troublesome operations such that whenever the blood collecting needle 51 is attached to or detached from the holder 55, the needle 51 has to be screwed into or out of the holder.
Accordingly, blood collecting tools, wherein a blood collecting needle and a holder are connected with the tools in a one touch operation by a fitting, instead of by screwing (Japanese Patent No. 28589/1989, Japanese Patent Application Laid-Open Nos. 297342/1990, 126630/1996 and 60827/2000, etc.), have been proposed. One of these blood collecting tools is a blood collecting needle 61 comprising a hub 62, a needle tube 63 and a resilient cap 64, and a holder 65 as shown in FIG. 2. The blood collecting needle 61 and the holder 65 are adapted such that a small diameter portion 621 formed on the hub 62 is engaged with a hub attaching and detaching mechanism 651 mounted on a distal end of the holder 65. Both of the attachment of the blood collecting needle 61 to the holder 65 and the detachment of the blood collecting needle 61 from the holder 65 are conducted with one touch by using the hub attaching and detaching mechanism 651.
However, the holder 65 having the hub attaching and detaching mechanism 651 is intended for the blood collecting needle 61 having the small diameter portion 621 as shown in FIG. 2. The blood collecting needle 51 having the thread portion 521 as shown in FIG. 1, instead of a small diameter portion, cannot be attached to the holder 65.
Meanwhile, a holder to which a blood collecting needle provided with a thread portion can be attached with one touch and from which the needle having the thread portion can be detached with one touch is also proposed (Japanese Patent No. 2723105). The holder has a structure that the thread portion of the blood collecting needle is fixed on a needle fixing unit mounted on the holder. The needle fixing unit intended for the needle having the thread portion can fix the needle more strongly than the hub attaching and detaching mechanism 651 shown in FIG. 2 which is intended for the blood collecting needle 61 having the small diameter portion 621. Nevertheless, such a holder having the needle fixing unit intended for the needle having a thread portion cannot certainly fix a needle having a small diameter portion instead of a thread portion.
As stated above, the conventional holder suits the particular type of blood collecting needle. Accordingly, a holder which suits both a blood collecting needle having a small diameter portion and a blood collecting needle having a thread portion has been developed (Japanese Patent Application Laid-Open No. 33509/1998). The holder described in the application comprises two fixing projections for fixing a needle hub of the blood collecting needle. The fixing projections of the holder fit not only the small diameter portion of the needle but also a valley portion of the thread portion of the needle. Therefore, the holder can fix both types of blood collecting needles.
However, such a holder which suits both of these types of blood collecting needles is complicated in structure and high in cost. Further, the force engaging the fixing projections of the holder with the needle is weaker than that of the hub attaching and detaching mechanism 651 of the holder intended for a needle having a small diameter portion and that of the needle fixing unit intended for a needle having a thread portion, and is not enough to fix the blood collecting needle.